The chief of U.S. airport security has been ousted amid widespread complaints from airline passengers about hours-long waits to get through security checkpoints at some of the country’s busiest airports.

A record 31.5 million people visited London in 2015, a roughly 4.7 percent increase from a year ago, according to London & Partners, the official promotional company for London. It marked the first time the number of visitors to London eclipsed the 30 million mark.